564 



From the porous nature of the chalk there is but little surface- 

 drainage, and that is supplied by the Mole and the Wey, which pierce 

 the chalk. 



6. Southern Division. 



The southern division has the Reading and Reigate Railway for its 

 northern boundary. The Wey and Arun canals form the western, the 

 county of Sussex the southern, and the turnpike-road from the direc- 

 tion of Horsham to Dorking, which also separates this division from 

 the south-eastern, constitutes the eastern boundary. The area is about 

 seventy-six square miles. 



This division is about equally divided between the lower greensand 

 and the wealden clay. The former, occupying the northern portion, 

 presents a series of barren wastes, which towards the south rise into 

 the bold and mountainous ridge of Leith Hill, which is 993 feet above 

 the level of the sea. The latter presents a uniform elevation of sur- 

 face, covered with extensive woods and coppices. 



This division is drained by various small tributary streams of the 

 river Wey. 



7. North-western Division. 



The north-western division is bounded on the north-east by the 

 river Thames from Weybridge, and terminates at Runnymede ; on the 

 south-west, by the county of Berkshire ; west, by the county of Hamp- 

 shire, to the South- Western Railway ; south and south-east, by the 

 Basingstoke Canal to Weybridge ; the area being about seventy-six 

 square miles. 



The whole of this division is of the London-clay formation, the 

 greater portion being covered with the Bagshot sand, which belongs 

 to the upper marine formation, and presents a poor, hungry, unim- 

 provable soil. Hence extensive barren heaths and wastes occur 

 throughout. This stratum forms, or covers, several eminences, as 

 Crawley Hill (west of Chertsey) and Bagshot Heath, and the high 

 grounds of Chobham Ridges. The greatest elevation does not ex- 

 ceed 463 feet above the level of the sea. Large masses of siliceous 

 sandstone, occurring in loose blocks, and called gray ivithersy are 

 found on Bagshot Heath. 



The principal portion of this division is drained by the Bourn 

 Brook, which enters the Thames below Chertsey. 



